Manufacture of lenticular prints



Sept. 6 @938 J. EGGERT ET AL MANUFACTURE OF LENTICULAR PRINTS Filed Jan. 3, .1935 2 Sheets-Sheet l Sept. 6, 1938. J. EGGERT ET'AL 2,129,205

MANUFACTURE OF LENTICULAR PRINTS 2 Sheets-Sheet 2 Filed Jan. 5, 1935 In venfors By Afforneys v Patented Sept. 6, 1938 2,129,205

2,129,205 MANUFACTURE OF LEN'I'ICULAR PRINTS John Eggert, Leipzig-Gohlis, and Gerd Heymer, Wollen Kreis Bltteri'eld, Germany, assignors to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-on-the-Main, Germany Application January 3, 1935, Serial No. 272 In Germany January 9, 1934 4 Claims. (CI. 88-24) Our present invention relates to the manufaction of the lenticular elements through any point ture of lenticular prints and more particularly to of the diaphragm cuts only one aperture correthe manufacture of lenticular prints wherein prosponding with a filter strip of the taking filter, jection printing is used. or an illuminating device as described in the co- One of its objects is to provide an improved pending application Ser. No. 634,070, filed Sept. process of manufacturing lenticular prints. Fur- 20, 1932 by Gerd Heymer, and in which there are ther objects will be seen from the detailed specifiused a plurality of lamps arranged in the plane cation following hereafter. that would be occupied by the multi-color filter Reference is made to the accompanying drawor itsvirtual image in the form of steps. Printings in which ing is thus effected that the point of intersection 10 Fig. 1 shows the condition in exposing a lenticof the filter middle lines in exposure lies within ular film according to this invention; the diaphragm of the printing objective which Figs. 2 and 3 show filters for use in accordance projects the image of the original film on the with the invention; printing film. If the print shall be projected with Fig. 4 shows some possibilities of arranging the another filter distance than that which is fixed diaphragm with relation to the objective and the r by the aforesaid condition a concave or a convex multl-color filter; lens may be inserted directly over the printing Fig. 5 shows an arrangement for exposing a film which projects the point of intersection of lenticular film with the aid of a multi-color filter the filter middle lines which is determinative for with repetition of the color sequence; and obtaining the correct color values to the required 0 Figs. 6, 7 and 8 show arrangements for printing distance, or generically expressed: the point of in accordance with the invention. intersection of the 'filtermiddle lines with relation In application Ser. No. 446,323, filed April 22, to the printing objective may be selected in such 1930' and matured into Patent No. 1,915,418, Gerd a manner that its apparent distance from the Heymer, one of the inventors of the present apprinting film corresponds with the required displication, has described a process for printing a tance of the projection filter always subject to the lenticular film on another lenticular fihn by ilcondition that the distance of this point from the luminating the negative film through the emoriginal corresponds with its distance from the bossed side. original in exposure.

30. This process is connected with the drawback Inasmuch as the filter must be arranged at a that a printing objective of very large aperture relatively large distance from the objective in must be used. In the co-pending application Ser. exposure, that is to say at a distance greater than No. 636,056, filed October 3, 1932, Gerd Heymer the focal length of the objective, an objective of has described a process which permits the use of very large aperture must be used in order that a printing objective with a smaller aperture by no vignetting takes place. However, it has been 5 inserting a convex lens in the trace of therays foundthat an objective of large aperture can be directly behind the negative. avoided if use is made of a filter with repetition According to the present invention we have of the color areas, 1. e., a filter the simple color found a process which permits the omission of sequence of which, red, green, blue is repeated 0 the aforesaid convex lens and simultaneously perentirely or partially in corresponding sequence mits the use of a printing objective that must not on both sides of the middle group. The size of have a very large aperture. This is attained by the exposure filter is such that the image of a photographing the object under such conditions color series red, green, blue projected on the emulon a lenticular film that the filter middle lines sion layer behind each lenticular element has that is to say the rays from the middle of the filter exactly the width of one lenticular element. In 45 to the middle of the lenticular elements, intersect order, when exposing the original film, to ensure in a plane on the emulsion side of the film, and completely uniform illumination of the picture illuminating the original through the embossed field, a mask of a certain shape may be inserted side under the same conditions which prevailed in-the vicinity of the objective. This mask con- 0 during exposure as regards the trace of the rays. sists of one or more rectangular pieces, all pieces 5 As a source of light there is used one which operof the same size having together such a width ates under local separation of the colors, for inthat, seen from the picture field, only a whole stance, a diaphragm having illuminated apertures multiple of a-color sequence red, green, blue is arranged in the form of steps, so that a line allowed to pass.

5 drawn in a direction perpendicular to the direc- The process may, of course, also be applied to 5 other combinations of filters, for example to the filter for the lenticular bi-pack, i. e., a bipack consisting of a lenticular front film and an ordinaryback film, as described in the application Ser. No. 608,829, filed May 2, 1932 by Gerd Heymer, and matured into Patent No, 1,968,944. In one modification the filter consists of a purple and a yellow filter strip. In this case the color strip sequence yellow, purple, takes the place of the color strip sequence red, green, blue mentioned above by way of example.

-The invention will now be further explained with reference to the accompanying drawings:

Fig. 1 illustrates first of all the production of a printing film to be used in accordance with the invention. N is the original film, A the exposure objective with the front focal point V. At F is placed the exposure filter. F is the plane conjugate with plane F and at a distance G from the film.

Figs. 2 and 3 illustrate examples of the shape of the repetition color filter and the diaphragm. Fig. 2 is a view of the filter as seen from the middle of the picture field. The middle portion of the breadth AB of the diaphragm allows just the middle group of the repetition filter to pass. To this middle portion of the diaphragm, for the purpose of further utilization of the objective to-. wards both sides, there are added portions of the width CA and BD, namely in such a manner that AC+BD=AB. ter for all points of the picture field is ensured.

Fig. 3 shows the same diaphragm seen from a lateral point of the picture field. It will be recognized that the relation of the three colors has remained unchanged, although the arrangement of the strips is not the same as in Fig. 2.

Fig. 4 illustrates various possible ways of arranging the diaphragm and the corresponding widths. ABCD is the repetition filter, E an objective. Until striking the objective, the rays are practically parallel and thence converge with an inclination, which varies with the construction of the objective, until they meet at the picture point P. In the case illustrated, the construction of the objective allows only two color sequences red, green, blue to pass simultaneously. The marginal portions of the diaphragm must therefore be shorter, as in Figs. 2 and 3. Now, as may be seen from Fig. 4, the width of the diaphragm aperture must vary according to whether the diaphragm is placed in position I, II or III. However, in certain circumstances in cases in which the number of the strips or the number of the filter units red, green, blue which can be used when the objective is full open, is larger, the diaphragm may be omitted without impairing the balance of the colors to any considerable extent.

Fig. 5 illustrates the arrangement of a repetition filter in which there is no fundamental alteration of the course of ray as compared with a filter with a simple color sequence. Here also, N is the original film, A the exposure objective with the focal point V: the repetition filter is arranged at F. The plane F is conjugate with the plane F. Its distance from the original=G.

Fig. 6 illustrates diagrammatically the arrangement in the printing process. Here again N is the original film, O the objective which projects the original N on to the printing film K. Now in order that the filter image of N may be located just in the vicinity of the objective 0 or within the objective, the distance of the exposure filter in the production of the original film N,

In this way agreement of the filmust be selected so that the value G shown in Figs. 1 and 5, is equal to the distance G between 0 and N during printing. The source of light is arranged opposite the lenticularembossing of the original N, namely, either, in accordance with U. S. Patent 1,915,418, there must be arranged a diaphragm system, or, in accordance with the co-pending application Ser. No. 634,070, filed Sept. 20, 1932 by Gerd Heymer, there must be arranged a step-shaped source of light in such a manner that it is conjugate with F. For this purpose the source of light is arranged at Lb, 12g, Lr and projected on the film N by means of the lens or lens system J.

Fig. 7 shows a modified printing arrangement. In this case in the arrangement shown in Fig. 6 the lens or lens system J arranged between the film N and the source of light b, i, L! is replaced by lens or lens system J arranged directly over the original N and focusing the source of light in the vicinity of the objective 0 or within this objective.

Fig. 8 shows the same printing arrangement as it is shown in Fig. '7 with the modification that a convex lens L has been placed directly over the printing film K, so that the filter image 1, g, b is displaced to r, g, b at the distance P from the printing film. Therefore, the multi-color filter for projecting the print must also be arranged at the distance P.

What we claim is:

l. A process of manufacturing lenticular prints which comprises exposing a lenticular film through a multi-color filter arranged at a distance from the taking objective greater than the focal length of said taking objective so that the middle filter lines intersect in a plane on the emulsion side of said lenticular, illuminating the original film thus taken through the embossed side under the same conditions as prevailed in exposure as regards the trace of the rays and under local separation of the colors, projecting the point of intersectiomof the filter middle lines at the same distance from the original film as said point had from the film in exposure, projecting the original on a lenticular printing film arranged with its lenticular elements facing the emulsion side of said original, and displacing the point of intersection of the filter middle lines with relation to the printing film to the distance required for the projection filter.

2. A process of manufacturing lenticular prints which comprises exposing a lenticular film through a multi-color filter with repetition of the sequence of color strips arranged at a distance from the taking objective greater than the focal length of said taking objective so that the filter middle lines intersect in a plane on the emulsion side of said lenticular film, illuminating the original film thus taken through the embossed side under the same conditions as prevailed in exposure as regards the trace of the rays and under local separation of the colors, projecting the point of intersection of the filter middle lines at the same distance from the original film as said point had from the film in exposure, projecting the original on a lenticular printing film arranged with its lenticularelements facing the emulsion side of said original, and displacing the point of intersection of the filter middle lines with relation to the printing film to the distance required for the projection filter.

3. A process of manufacturing lenticular prints which comprises exposing a lenticular film through ,a multi-color filter with repetition of the from the taking objective sequence of color strips arranged at a distance greater than the focal length of said taking objective so that the filter middle lines intersect in a plane on the emulsion side of said lenticular film, masking the rays during exposure so that at least one sequence of color strips is visible when viewed from the film while avoiding vignetting, illuminating the original film thus taken through the embossed side under the same conditions as prevailed in exposure as regards the trace of the rays and under local sep ration of the colors, projecting the point of intersection of the filter middle lines at the same distance from the original film as said point had from the film in exposure, projectthrough a multi-color filter with repetition of the sequence of color strips arranged at a distance from the taking objective so that the filter middle lines intersect in a plane on the emulsion side of said lenticular film, masking the rays during exposure so that sequences of color strips are visible when viewed from the film which sequences have different lengths and the same breadth and the strips forming one sequence having the same length while avoiding vignetting, illuminating the original film thus taken through the embossed side under the same conditions as prevailed in exposure as regards the trace of the rays and under local separation of the colors, projecting the point of intersection of the filter middle lines at the same distance from the original film as.

said point had from the film in exposure, projecting the original on a lenticular printing film arranged with its lenticular elements facing the emulsion side of said original, and displacing the point of intersection of the filter middle lines with relation to the printing film to the distance required for the projection filter.

JOHN EGGER'I. GERD HEYMER. 

